Remembering touch: using interference tasks to study tactile and haptic memory

Abstract

We review the literature on sensory, short-term, long-term, and working memory for tactile and haptic inputs, focusing on research using interference tasks and issues arising from the use of this methodology. We then present two studies that investigated the effects of haptic, verbal, spatial, and motor interference on haptic object recognition. Experiment 1 was an old/new object recognition task with the interference tasks performed during encoding of the study objects. Experiment 2 was a sequential object-matching task with the interference tasks performed in the retention interval between presenting the two objects. Different results were found across the two experiments and the pattern of interference obtained was different again in two similar studies that also used interference tasks to investigate haptic object recognition (. Lacey & Campbell, 2006). Haptic, spatial, visual, and verbal interference all significantly disrupted performance on the primary haptic object recognition task in some studies but not in others. We argue that the selection and use of primary and secondary tasks in interference studies need to be more theoretically motivated and, where possible, standardized before general conclusions can be drawn about haptic memory using this methodology. However, notwithstanding these issues, the current findings suggest that verbal and visual processes have a role during the haptic encoding of objects whereas haptic and spatial, but not motor, processes are important for maintaining the representations of objects presented haptically. We further suggest that whereas verbal strategies may be employed in some haptic memory tasks, the underlying representations are likely spatial in nature.